具间断系数的N维拟线性椭圆方程弱解的正则性

讨论了具间断系数的N维拟线性椭圆方程. 利用估计和差分逼近方法,证明了弱解的一阶导数H\"{o}lder连续到方程系数间断的内边界.     

含不连续系数的p-Laplace抛物方程的正则性［英文］

当系数矩阵满足一定的VMO条件时,利用Campanato凝固系数方法,证明一类退化抛物方程弱解的Morrey正则性.并且,利用H?lder连续函数的积分特征,对方程弱解建立局部最优H?lder连续性.     

含不连续系数的p-Laplace抛物方程的正则性(英文)

当系数矩阵满足一定的VMO条件时,利用Campanato凝固系数方法,证明一类退化抛物方程弱解的Morrey正则性.并且,利用H?lder连续函数的积分特征,对方程弱解建立局部最优H?lder连续性.     

自然增长的半线性次椭圆方程内部H?lder估计

对于低阶项满足自然增长条件的半线性次椭圆方程有界弱解,通过Moser-Nash迭代和弱Harnack不等式,得到弱解的内部H?lder连续性估计.     

Banach空间值的变指标Lebesgue空间上的Calderón-Zygmund算子（英文）

本文证明了带有满足H?rmander条件的算子核的向量值的Calderón-Zygmund算子在齐型的度量测度空间上的指标为全局log-H?lder连续的变指标Lebesgue空间上的有界性.作为应用,得到了向量值的Hardy-Littlewood极大算子在齐型的度量测度空间上的指标为全局log-H?lder连续的变指标Lebesgue空间上的有界性.     

一类非散度型椭圆方程解的梯度估计

得到了一类非散度型二阶椭圆方程解的梯度在 Lp中的局部估计 ,其中 p >0 .方程形式为 :L0 u+ b .　Δu -vu =f,L0 为具 H lder连续系数的非散度型椭圆算子 ,f有界可测 ,| b| 2 与 v均属于 Kato类     

自然增长下非线性退化椭圆方程的优化Hlder连续指数

利用Moser-Nash迭代和稠密引理,得到了在自然增长下的非线性退化椭圆方程有界弱解具有某一Hlder指数的正则性;在已知数据的进一步正则性下,建立了具有任意γ满足0≤γ<κ的优化Hlder连续性指数,其中κ是A-调和函数的局部Hlder连续指数.     

热传导方程解的部分Schauder估计

该文主要研究热传导方程的解u的部分正则性,得到了u的部分Schauder估计的积分形式的统一表达式,即当非齐次项f关于某一个方向Lipschitz连续,Hlder连续或者Dini连续时,部分Schauder估计均可由该表达式推出.特别地,当方程的非齐次项f沿x_n方向Hlder连续时,混合偏导数u_(xxn)是Hlder连续的.     

薛定谔型椭圆方程解的正则性（英文）

利用奇异积分理论,得到具有薛定谔型椭圆方程解的局部正则性估计,其中位势函数属于反Hlder类.     

自然增长下次椭圆A-调和方程的H?lder连续性估计

通过Moser-Nash迭代方法并结合密度引理,研究了一类A-调和型次椭圆方程在自然增长下的有界弱解的局部H?lder连续性.     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Generalization of the interaction between Haar approximation and polynomial operators to higher order methods

In applications it is useful to compute the local average empirical statistics on u. A very simple relation exists when of a function f（u） of an input u from the local averages are given by a Haar approximation. The question is to know if it holds for higher order approximation methods. To do so, it is necessary to use approximate product operators defined over linear approximation spaces. These products are characterized by a Strang and Fix like condition. An explicit construction of these product operators is exhibited for piecewise polynomial functions, using Hermite interpolation. The averaging relation which holds for the Haar approximation is then recovered when the product is defined by a two point Hermite interpolation.     

Jacobi polynomials used to invert the laplace transform

Given the Laplace transform F(s) of a function f(t), we develop a new algorithm to find an approximation to f(t) by the use of the classical Jacobi polynomials. The main contribution of our work is the development of a new and very effective method to determine the coefficients in the finite series expansion that approximation f(t) in terms of Jacobi polynomials. Some numerical examples are illustrated.